How to Track Down the Real Cause of Sudden Latency Spikes
Start with distributed tracing to find which service is slow, then use continuous profiling to see why the code is slow, and finally apply high-cardinality analysis to identify which users or conditions trigger the problem. It's 2 AM. Your phone buzzes. Users are reporting timeouts. The metrics dashboard shows p99 latency spiking from 200ms to 4 seconds, but everything looks normal—CPU at 60%, memory stable, no error spikes. A quick pod restart helps briefly, then latency climbs right back up.